Metallic composition



Patented May 19, 1925.

UNITED STATES PATENT OFFICE.

EDWIN F. xmesnomr, or RUTH RFORD, NEW JERSEY, ASSIGNOR 'ro WESTERN ELEC- TBIC COMPANY, mconrom'ran, or NEW YORK, n,- Y., A oonroaa'rron or NEW YORK.

No Drawing.

To all whom it may concern:

Be it known that I, .Enwnr F. Kmcs- BURY, a citizen of the United States of America, residing at- Rutherford, in the and its object is to provide a satisfactory used with the usual metal for use as a wire contact member.

In accordance with the features of the invention, there is provided a metallic composition which will when formed into grid wires for co-ordinate switches such as employed in automatic telephone impulse-sending apparatus. It is necessary that such a metal have a low contact resistance, a maximum life in spite of the mechanical wear to which it is subjected, and but little tendency to be electrically corroded by arcing especially when hosphor bronze contact members of (to-ordinate switches. The metal should also be tough, reasonablycheap, and comparatively homogeneous, and should have a good tensile strength. It should also be of such'a character that it will not cause contact memberscomposedof such a. metal as phosphor-bronze to be rapidly worn out.

' It has been found that a metallic composition comprising about 10 to 50 per cent give eflicient service xEmLLIc conrosr'rron. r

, ilpplioatlon fled August 14,1923. Serial No. 657,435.

. of, silver, about 1 to 5 per cent of tin,

and about 45 to 88 percent of copper possesses these ualities to a marked degree and is excee ingly satisfactory for use as grid wire to be employed with phosphorbronze contacts in co-ordinate switches or similar apparatus. An alloy containing these metals in the following proportions has proved the most satisfactory for this purpose, silver 15 per cent, tin 2.- per cent, and copper 83 per cent. The tin content, however, may be raised to 4 per cent and the. copper content correspondingly decreased without any marked change in the efficiency of the alloy.

The invention claimed is:

1. A metallic composition comprising as the essential elements thereof the following metals in substantially the following'proportions, silver 10 to 50 per cent, tin 1 to 5 per cent, and copper 45 to 88 per cent.

. 2. A contact alloy comprising as the essential elements thereof the following metals in substantially the following proportions, silver 15 per cent, tin.2 to 4 per cent, and copper 81 to 83 per cent. i

3. A grid wire to be used with phosphorbronze contact members, which; is composed of thefollowing metals in substantially the following proportions, silver 15 per cent, tin 2 per cent, and copper 83,per cent.

In witness whereof I hereunto subscribe my name this 8th day of August, A. D.,

EDWIN F. KINGSBURY. 

